---
title: "Create your own Eval"
description: "Kastrax allows so create your own evals, here is how."
---

# Create your own Eval

Creating your own eval is as easy as creating a new function. You simply create a class that extends the `Metric` class and implement the `measure` method.

## Basic example

For a simple example of creating a custom metric that checks if the output contains certain words, see our [Word Inclusion example](/examples/evals/word-inclusion).

## Creating a custom LLM-Judge

A custom LLM judge helps evaluate specific aspects of your AI's responses. Think of it like having an expert reviewer for your particular use case:

- Medical Q&A → Judge checks for medical accuracy and safety
- Customer Service → Judge evaluates tone and helpfulness
- Code Generation → Judge verifies code correctness and style

For a practical example, see how we evaluate [Chef Michel's](/docs/guides/chef-michel) recipes for gluten content in our [Gluten Checker example](/examples/evals/custom-eval).
